This invention relates to the preparation of 1,3-propanediol, especially to a cobalt-catalyzed process for manufacturing 1,3-propanediol in high yields without the use of a phosphine ligand for the cobalt catalyst.
1,3-Propanediol (PDO) is an intermediate in the production of polyesters for fibers and films. It is known to prepare PDO in a two-step process involving (1) the cobalt-catalyzed hydroformylation (reaction with synthesis gas, H.sub.2 /CO) of ethylene oxide to intermediate 3-hydroxypropanal (HPA) and (2) subsequent hydrogenation of the HPA to PDO. The initial hydroformylation process can be carried out at temperatures greater than 100.degree. C. and at high syngas pressures to achieve practical reaction rates. The resulting product mixture is, however, rather unselective for HPA.
Alternatively, the cobalt catalyst has been used in combination with a phosphine ligand to prepare HPA with greater selectivity and at lower temperature and pressure. However, the use of a phosphine ligand adds to the cost of the catalyst and increases the complexity of catalyst recycle.
There are a number of prior art references which relate to 1,3-propanediol production including the step of hydroformylation of ethylene oxide using a cobalt catalyst in the absence of a phosphine ligand, using other ligands. See, for example, the following U.S. Pat. Nos. 5,981,808, 5,463,145, 5,463,146, 5,545,767, 5,731,478, 5,723,389, 5,786,524, 5,841,003, 5,576,471, 5,563,302, 5,545,765, 5,463,144, 5,770,776 and 5,585,528.
U.S. Pat. No. 4,096,188 describes the preparation of straight chain olefins by catalytic hydroformylation with carbon monoxide and hydrogen in the presence of cobalt catalyst and primary, secondary or tertiary amine modifier.